Why do we still have signal bars on cell phones?

In TWiT 255: You’re Holding It Wrong they had an interesting discussion about the antenna issues with the iPhone 4. They pointed out that most all cell phones have issues with reception if you hold the phone certain ways. The iPhone just happens to have made the place not to hold the phone more visible. Cell phones need antennas and unless you want to go back to the days of pull-up antennas this is just a fact of life. Granted Apple probably could have given a bit more thought into the placement of the antenna but frankly given the size of the device they don’t really have many choices of were to put the darn thing.

One thing I found particularly interesting in this podcast was a point that Jerry Pournelle made about why we even have bars to represent signal strength on phones anymore. It made sense back when phones used analog signals and the quality of the call would go down if you had a bad signal. Today with most all phones being digital this doesn’t make sense. With a digital signal it either works or it doesn’t. You can either make a call or you can’t. The signal strength shouldn’t affect the quality of the call. You call may be dropped if the signal gets too low but the quality shouldn’t change. Is this just a hold over from the analog days or is there really some reason for these bar besides the fact that the marketing people like them?

3 thoughts on “Why do we still have signal bars on cell phones?

  1. Radio signals are part of the physical world, so they are analog. To enable them to carry digital signals, there are something called forward error correction codes included in the signal. That enables the transmission to deal with a certain number of errors in a package of digital data before the whole package has to be retransmitted. The bars describe how many errors there are in the digital data, which correlates to the strength of the signal.

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